Sole assembly and footwear comprising a sole assembly

ABSTRACT

The inventive subject matter is generally directed to a sole assembly comprising a plurality of traction elements disposed on a ground-facing surface of the sole assembly, and wherein the sole assembly is configured to provide a rocker effect. In some embodiments, the inventive subject matter is directed to a sole assembly that includes a spring system based on a semi-rigid polymer shaped to provide the rocker effect. In some embodiments, the inventive subject matter is directed to a golf shoe with a sole profile having a geometric shape that provides a roll-over effect according to rocker shoe technology and wherein the sole profile is optimized to convey the benefits of rocker shoe technology to golf specific activities.

RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/522,655, filed Aug. 11, 2011, by Hermann Oberschneider et al. entitled TRACTION FOOTWEAR, the contents of which are hereby incorporated by reference as if recited in full herein for all purposes.

BACKGROUND

The inventive subject matter is generally directed to footwear. In some embodiments, the inventive subject matter is directed to footwear having a traction sole, especially a sole for use in the sport of golf. The footwear includes a sole with a rocker sole that requires a user to engage core muscles and balance. In other embodiments, the inventive subject matter is directed to a rocker shoe with a midsole based on certain spring systems.

The concept of walking with a rolling action is said to result in a comfortable heel strike, creating a natural instability that can help the body generate muscle activity in the lower limbs. This action can be facilitated by a shoe with a pivot axis positioned between the heel and toes. For example, the axis may be based on a convexly curved sole with its integrated balancing area requiring an active and controlled rolling movement that can help the body to improve balance and posture while standing and walking. Footwear enabling this particular way of walking has been described, for example, in U.S. Pat. No. 6,341,432 which is hereby incorporated by reference in its entirety for all purposes. As illustrated in FIG. 1, the rocker action described in that patent is achieved by a shoe that provides a recess or resiliently collapsible zone within sole 3 that extends from a rear heel area 12 through a metatarsal area 11. The recess is filled with a relatively soft material element 109. A pivot axis 21 is disposed at the distal end of the collapsible zone 111. Forward of the collapsible zone 111 is a firmer support zone 112 onto which the rocking motion is completed.

When the shoe 1 is placed on a support surface in the vicinity of the pivot axis 21, it tilts around the pivot axis 21 with the ball or toe area 10 of the shoe 1 on the support. As a result, the foot and the lower leg are displaced slightly forward and the knee is automatically bent slightly. A leg bent at the knee accepts the impact load through the bones of the skeleton and the surrounding musculature without the impact load being transmitted to the joints or the spinal column The prior art shoe produces a rounding effect, in other words a rolling action, as it is placed on the support so that the impact load exerted on the sensitive joints or on the spinal column is considerably reduced. In the standing phase, the wearer of the shoe 1 is also placed in a therapeutic posture, in other words a posture with the knees forced to bend at an angle so that the spinal column is also relieved of a load when standing.

Other examples of rocker shoes include US 2011/0078923, US 2011/0035960, US 2010/0263233, US 2010/0281716, US 2009/0151201 and WO 2006/065047, which are hereby incorporated by reference in their entireties for all purposes.

Because of the pivot axis in rocker shoes, these shoes cause some natural instability that forces users to engage core muscles. The pivotable bottom structure acts on major parts of the postural and supporting musculature, because the body must now be actively kept in balance. To maintain a stable standing position, continuous minimal compensating movements are required. In particular, neglected muscles are trained, posture and gait pattern are improved, and the body is toned and shaped.

Unfortunately, the prior art shoes have not been adapted for special purpose athletic shoes that have traction elements, e.g., spike or cleats, such as golf shoes, football shoes, soccer shoes, baseball shoes, track shoes, etc. The inclusion of traction elements, such as spikes and cleats is inconsistent with and counterintuitive to the notion of a smooth, rocker motion, so the lack of rocker shoes incorporating traction elements is not surprising. Hereinafter, golf shoes will be discussed as a representative form of traction footwear, although some or all the discussion concerning golf shoes will apply to other kinds of shoes with traction elements.

As used herein a “traction element” generally refers to relatively discrete structural components on the ground-engaging surface of a sole, such as spikes and cleats. For golf, baseball, football, and soccer shoes, the traction elements protrude substantially from their supporting surface and are intended to dig into softer surfaces such as grass, dirt, mud, and artificial surfaces such as tracks.

In golf sports, desired features include that the shoes are lightweight, support the foot, and have a spike formation that offers the desired traction and stability on a golf course. In addition to providing support and comfort to the foot while walking, golf shoes support and stabilize the golfer when the golfer is swinging and hitting the golf ball, resulting in a better posture and improved balance. Other desirable features for a golf shoe are a sole that allows the golfer to stand lower in the shoe, that provides a better feel for the course, and that provides a lower center of gravity. Again, all these desirable characteristics are counter to the notion of a rocker shoe with a pivot axis.

There have been several attempts to improve cushioning and support in conventional athletic shoes. For example, polymer spring units have been placed in portions in the sole, particularly the heel portion, and in some cases the forefoot portion. See, for example, U.S. Pat. No. 4,910,884; U.S. Pat. No. 5,337,492; U.S. Pat. No. 5,461,800; and U.S. Pat. No. 6,625,905, which are hereby incorporated by reference in their entireties for all purposes. However, despite the availability of many kinds of conventional shoes, golf-related injuries are a common problem often caused by improper golf swing or improper posture. Associated activities such as pushing and pulling carts or carrying bags may also cause injuries. Moreover, golf is also a demanding sport that requires precise balance, timing and coordination of musculature through the golfer's swing. Therefore, there is an ever present need for improved training devices that will help golfer's improve their swings and maintain posture.

Accordingly there is a need for an improved sole assembly for traction footwear, such as golf shoes, that includes the features of a rocker sole to enhance awareness of balance, posture, and gait patterns, as well as improving coordination and providing a better feel for the course.

SUMMARY

The inventive subject matter is generally directed to a sole assembly comprising a plurality of traction elements disposed on a ground-facing surface of the sole assembly, and wherein the sole assembly is configured to provide a rocker effect. In some embodiments, the inventive subject matter is directed to a sole assembly that includes a spring system based on a semi-rigid polymer shaped to provide the rocker effect. In some embodiments, the inventive subject matter is directed to a golf shoe with a sole profile having a geometric shape that provides a roll-over effect according to rocker shoe technology and wherein the sole profile is optimized to convey the benefits of rocker shoe technology to golf specific activities.

The foregoing is not intended to be an exhaustive list of embodiments and features of the inventive subject matter. Persons skilled in the art are capable of appreciating other embodiments and features from the following detailed description in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures show embodiments according to the inventive subject matter, unless noted as showing prior art.

FIG. 1 shows a side, sectional view of an example of a prior art shoe that is configured to provide a rocker effect.

FIG. 2 is a bottom-side perspective view of one embodiment of sole assembly for a shoe (left).

FIG. 3 is a front-side perspective view of the embodiment of FIG. 1.

FIG. 4 is a side view of the embodiment of FIG. 1.

FIG. 5 is a front-bottom perspective view of the embodiment of FIG. 1.

FIG. 6 is a rear-side perspective view of the embodiment of FIG. 1.

FIG. 7 is a bottom view of the embodiment of FIG. 1.

FIG. 8 is a crossectional view of a shoe comprising an upper and the sole assembly of FIG. 1.

FIG. 9 is an elevational view of the lateral side of another possible embodiment of a sole assembly for a shoe (left).

FIG. 10 is a rear-side perspective view of the embodiment of FIG. 9.

FIG. 11 is a front-bottom perspective view of the embodiment of FIG. 9.

FIG. 12 is a front-side perspective view of the embodiment of FIG. 9.

FIG. 13 is a top view of the embodiment of FIG. 9.

DETAILED DESCRIPTION

Representative embodiments according to the inventive subject matter are shown in FIGS. 2-13, wherein the same or generally similar features share common reference numerals.

According to one embodiment of the invention, a sole assembly 4 for a shoe 1 comprising a foot-supporting element and a ground-engaging element is provided. The foot-supporting element 6 and the ground-engaging element 8 are separated in vertical direction by means of a spring system 7 and interconnected at least at the toe end 13 and heel end 14 of the sole assembly. The spring system is compressible in a vertical direction, in particular under vertical load exerted by a foot, so that at least a section of the ground-engaging element approaches the foot-supporting element in vertical direction under the vertical load. Further, the ground-engaging element is convexly shaped at least in a midfoot section. The midfoot section may be referred to as the longitudinal middle third section of the sole assembly. The convex or outwardly bent curvature of the ground-engaging element helps to provide a rocker action or tilting movement of the shoe. Further, the combination of the convex curvature and the spring system provides a feedback to the wearer of the shoe, thereby indicating the position of the actual balance point.

The ground-engaging element 8 is preferably generally plate shaped. As well, the foot-supporting element 6 may be plate shaped. Of course, in this regard the term “plate-shaped” does not refer to a flat or planar plate. Rather, as the ground-engaging element has a convex curvature, this element has the form of a bent plate. The foot-supporting element may be bent as well so as to contour or adapt to the foot sole.

In some embodiments, the inventive subject matter overcomes the aforementioned problems by providing traction footwear having an outer sole profile with a specific geometric shape and/or sole structure that allows a rocker effect. The sole profile and structure may be optimized to convey the benefits of rocker shoe technology to golf specific activities such as walking, performing T-shots, fairway shots, sand shots, and putting. By incorporating the features of rocker action in a golf shoe, the user experiences some instability, which leads to more awareness of balance and posture.

In another embodiment, the inventive subject matter is directed to a sole assembly 4 for traction footwear that includes a spring system 7 positioned between a foot-supporting element 6 and a ground-engaging element 8 so that the spring system provides a resiliently collapsible or compliant forefoot 16, midfoot 17, and/or heel section 18 to the sole assembly.

In some embodiments, the spring system 7 allows for a heel section 18 that is relatively more compressible than a midfoot section 17 and/or forefoot section 16 so that the sole can provide the rocker action.

In other embodiments, the foot-supporting element 6, ground-engaging element 8, and spring system 7 define a sole assembly 4 that provides a rocker shoe effect with a rolling action around a pivot axis 21. In further embodiments, the foot-supporting element and ground-engaging element may be separate elements that are functionally coupled by a resilient material and/or structure that serves as a deforming means from a heel area to the pivot axis, and coupled with a more rigid structure in a distal area forward of the pivot axis. In further embodiments, the foot-supporting element, ground-engaging element, and spring system may be integrated as a single monolithic piece. For example, they may all be molded together in a single shot or multiple shot injection molding process. Furthermore, different sections may have different materials or material properties to create a sole that is tuned to desired functions discussed herein.

A shoe 1, such as a golf shown in FIG. 8, has a sole assembly 4 and an upper portion 5 that is coupled to the sole assembly and sized to receive a foot. The sole assembly may have a forefoot section 16, a heel section 18, and a midfoot section 17, as shown, for example, in FIG. 4. The forefoot section of the sole is the section that corresponds approximately to the area covered by the toes and metatarsals of a foot. The midfoot section of the sole is the section that is corresponds approximately to the area of the foot where the metatarsal bones are linked to the irregularly shaped tarsal bones, which form the foot's arch. The heel section corresponds approximately to the heel of the foot linking the midfoot to the ankle including the area below the talus and calcaneus.

The sole assembly 4 includes a foot-supporting element 6. In the embodiments shown in the figures, the foot-supporting element is a curved top plate. The foot-supporting element may be made of a rigid or semi-rigid material that will work as a stop surface 108 for the compliant or collapsible ground-engaging element in the heel section. In some embodiments, the foot-supporting element may include a thermoplastic polyurethane plate. Examples of other suitable materials include Urethane, Hytrel, Pebax, Nylon, etc. To provide both sufficient stiffness and resilience, a non-elastomeric material, at least for the load bearing sections of the ground-engaging element, may be used. For example, the ground-engaging element may be fabricated from a fiber-reinforced composite material. The foot-supporting element may have an upper surface and a lower surface. The upper surface of the foot-supporting element may support the foot directly or indirectly, for example, via an insole or an insert.

The sole assembly 4 further has a ground-engaging element or bottom layer 8. FIGS. 2-14 show a ground-engaging element being a thin layer of material that is coupled to the foot-supporting element and intermediate spring system. The ground-engaging element has a ground facing surface and a top, foot-facing surface. The ground-engaging element is generally coextensive with some or all of a wearer's forefoot, midfoot, and/or rearfoot. Not necessarily all of such areas will actually engage the ground during use. For example, a ground-engaging element with a high arch may not engage the ground. Accordingly, the phrase “ground engaging” generally refers to an outsole structure or other ground facing structure, which has some or all portions that engage the ground.

The contours of the ground-engaging element 8 may have a shape that is substantially convex along a longitudinal cross-section of the sole when the shoe is in the unloaded state. The curved profile of the ground-engaging surface may have radial dimensions that are beneficial for playing golf.

In some embodiments, the apex of the convex shape may be positioned slightly off the center of the shoe along the longitudinal direction, for example the apex may be shifted towards the heel of the shoe. In other embodiments, the apex of the convex shape may be shifted towards the lateral or medial side of the shoe. FIG. 4 shows a side view of a sole assembly 4 wherein the profile of the ground-engaging element 8 follows a convex shape wherein the forefoot portion has a larger radius than that of the heel portion and wherein the apex of the convex shape is positioned below the arch of the foot. In some other embodiments, a convexly shaped sole may have a pivot direction that is slightly offset from the longitudinal axis of the shoe, for example, allowing a shoe sole to pivot in a rolling action towards lateral or medial sides of the shoe.

In other embodiments, the configuration of the sole assembly 4 may have any shape and structure that allows achieving desired degrees of rocking, stability, and controllability. For example, the sole assembly may have a geometrical form, such as polygonal shapes that approximate a curve, that allows for pivoting around an axis 21. In further possible embodiments, an outer sole structure may be a generally planar structure that allows for a yielding placement upon use within certain areas of the sole assembly. For example, this could be achieved by constructing areas with different durometer so that portion are collapsible or compressible under load to form a shape that allows pivoting.

The ground-engaging element 8 may be made of the same material as the foot-supporting element, for example a rigid or semi-rigid material with a hardness of 45-75 Shore D. A flexible and soft ground-engaging element could also be used. For example, a rubber or synthetic outsole material could be used and may be held in the convex shape by an intermediate spring system and/or a foot-supporting element.

In the embodiments shown, the ground-engaging element 8 is joined directly to the foot-supporting element 6 at a toe end 13 and at a heel end 14 of the sole assembly, and is integrated with a spring structure 7 to form a unitary sole assembly 4. In the finished shoe, the sides of the sole assembly may be left open or covered with any suitable material.

The rocker effect of the sole assembly 4 may be accomplished by a spring system 7 that provides a support zone in a forefoot section 16 to midfoot section 17 of a shoe and that allows for a collapsible or compliant zone 19 in a midfoot to heel section 18, for example, as shown in FIG. 4. Thus, according to one embodiment of the invention, the spring system has a spring constant that varies in longitudinal direction. In particular, the spring constant may be lower in the heel section compared to the forefoot section.

The terms “spring system” and “spring” are used herein broadly to refer to any intermediate structure or material that stores mechanical energy in the sole and resiliently allows the sole to return to its original shape after deformation. This property may be conferred to the sole assembly by an elastic object or material that, when compressed in the vertical direction of the shoe sole, exerts a restoring force which tends to bring the object/material and shoe sole back to its original height. A spring system 7 may include any type of resiliently compressible mechanism such as a mechanical structure, for example coiled springs, tension springs, hinged springs, tubular springs, collapsible ribs, bladders, air bellows, etc., as well as any type of resiliently compressible filling material, such as an open-pored plastic materials or foams.

In some embodiments, the spring system 7 may be formed by the combination of the foot-supporting element 6, ground-engaging element 8, and an intermediate structure, e.g., structure 70, sandwiched between the foot-supporting element and ground-engaging element. In other embodiments, the spring system may be formed as an integral part of the foot-supporting element and/or ground-engaging element.

In the embodiments shown, the spring system 7 is formed by structurally integrated elements that show a wavy or undulating profile in a longitudinal cross-section of the sole. Accordingly, the spring system according to this embodiment of the invention comprises a spring having an undulating profile, e.g., a zigzag profile, which undulates along the longitudinal direction of the sole assembly. According to a refinement of the invention, the wavy pattern has a peak-to-peak length that increases towards the midfoot/heel sections of the sole assembly 4, or from the toe end towards the heel end. FIG. 4 shows a side view along the medial side of a sole assembly with such a wavy pattern. FIG. 8 shows a cross-sectional view of the sole assembly 4. The spring system starts in the toe section or forefoot section 16 of the sole and runs towards a midfoot section 17. The spring system supports the ground-engaging element 8 from the forefoot section to about the midfoot section. The overall height of the wave is smallest at the toe end 13 and the height increases towards the midfoot section. The height of the wave profile reaches a maximum trough (at the apex of the convexity) at about a pivot axis 21 of the sole assembly. In some embodiments, the wavy profile continues towards the heel section 18 and ends with a peak at the foot-supporting element 6.

The wavy pattern may have increasing wavelengths from a toe end 13 of the sole assembly 4 towards the pivot axis 21. The spring system 7 in the forefoot section 16 and partially in the midfoot section 17 forms the support zone of the shoe sole. FIG. 8 shows how peaks of the wavy pattern touch the foot-supporting element 6 four times and how the troughs of the wave pattern touch the ground-engaging element also four times in the support zone of the sole. However, there may be more our less such tangents resulting from the undulation pattern. The wavy spring system ends in the heel section 18 proximal of the pivot axis with a structure that runs upward from about the pivot axis into the heel area and ends where the structure touches the foot-supporting element. Such a spring system provides the sole assembly with a rigid forefoot section and a deformable heel section 18 to the sole assembly. It is also clear from FIG. 4 and FIGS. 8-9, for example, that the overall thickness of the sole assembly is considerably greater than the thickness of the ground-engaging element. Thus, without restriction to the specific embodiment as shown in the figures, the maximum thickness of the sole assembly in at least the midfoot region measured from the bottom surface of the ground-engaging element to the top surface of the foot-supporting element may advantageously be at least three times greater than the thickness of the ground-engaging element. Generally, a thin plate thickness of the ground-engaging element is preferred. According to one embodiment, the thickness of the ground-engaging element is less than 5 millimeters, preferably less than 4 millimeters. According to a specific embodiment, the thickness of the ground-engaging element is between 2 and 3 millimeters. As persons skilled in the art will appreciate, the relative thicknesses will vary according to materials used and effects desired.

FIGS. 2, 3 and 6, for example, show a spring system 7 that is formed by tubular members 70 running in a transverse direction of the sole assembly and alternating pockets or chambers that are substantially free of material. The structure may be coupled to and/or integrated with the foot-supporting element 6 and/or ground-engaging element 8, or loosely interact with these surfaces. In some embodiments, the spring system, and even the entire midsole or sole unit, may be formed as a single monolithic piece that is wedged between the foot-supporting element and ground-engaging element. In other embodiments, the spring system may be formed by multiple parts that are interconnected to form the spring system or that are coupled to the foot-supporting element and/or ground-engaging element to obtain the desired spring effect. For example, a plurality of structural webs may extend between the foot-supporting element and ground-engaging element.

FIGS. 2-8 show an embodiment wherein the heel portion is substantially free of spring systems. In other embodiments, such as that of FIGS. 9-13, a series of tubular suspension members 70 or reinforcing ribs may be positioned in a transverse direction along the sole to provide resiliently loadable springs.

FIGS. 9-13 show another embodiment of a sole assembly wherein the spring effect is accomplished with a single molded piece. The sole assembly includes a spring system 7 with a set of tubular members 70 extending between the foot-supporting element and the ground-engaging element. The set of tubular members 70 is configured in a wavy profile, providing for a relatively soft heel portion and a firmer forefoot portion and wherein the wavy profile terminates in the heel section by curling down from a peak of the wave, at the foot-supporting element, to the ground facing element. Rearward of that curled down portion 74 is another spring structure 75 at heel end 14 that interconnects foot-supporting element 6 and ground-engaging element 8.

The rolling action of the sole assembly 4 is accomplished by a pivot 20 defined by pivot axis 21 which extends in the transverse direction of the sole assembly, for example, as shown in FIGS. 4, 5, and 8. The pivoting movement is accomplished by the rolling action provided by the convex shape of the sole assembly. Alternatively, a generally planar sole assembly may allow a more yielding placement of the shoe on a support surface corresponding with a midfoot or heel area, thereby resulting in a rocker action. A softer heel area may also be combined with a more distal convex shape on the sole for an accentuated rocker effect.

The pivot axis 21 may be located in a midfoot section 17, which may extend over approximately one-third of the length of the shoe. For example, the pivot axis may be in an area between the lengthwise center of the shoe and a heel area. FIGS. 4 and 8 show pivot axis 21 at approximately the lengthwise center of the shoe. In other embodiments, the pivot axis may be at a location distal of center towards a forefoot section 16 of the shoe assembly.

The heel area pivots away upward around the pivot axis 21 when a user walks on a supporting surface. The shoe produces a rolling action as it is placed on a support surface so that the impact load exerted on the sensitive joints or on the spinal column is considerably reduced.

The wavy profile, shown in FIGS. 4 and 8, for example, starts at the toe end 13 of the shoe and the wavelength progressively increases from the toe end towards the lengthwise center of the shoe where a trough of the wave maximizes at pivot axis 21. As shown in the side views of the shoe sole assembly, the trough of the wave touches the ground-engaging element 8 at the pivot axis. The wavy structure further continues towards the heel end 14 of the shoe and the wave peaks and ends below the heel area by touching the foot-supporting element 6, leaving the heel section substantially free of spring system. In the forefoot section 16, the sole structure provides dimensional stability and/or flexural strength.

Examples of suitable materials for a spring system 7 include resiliently compressible materials, such as urethane, Pebax, Hytrel, etc.

The ability to control the spring constant by the structural and/or material features can be used in various combinations to precisely control the performance characteristics of the sole assembly. Variations in the longitudinal profile, transverse profile, spring-thickness, spring shape, and wall thickness of the sole assembly permit control over the spring force in response to compression.

Optionally, the sole assembly 4 may include a foam material interspersed with the spring material, for example in the pockets or voids 37, 71 of tubular members 70. In some embodiments, the midsole may be free of foam material, for example a foot-supporting element, ground-engaging element, and sidewalls forming an open midsole that houses a spring system. In other embodiments, at least a portion of the midsole may be free of foam material, such as a heel portion. In further possible embodiments, a spring system may be embedded in a foam material, such as urethane, ethyl-vinyl-acetate (EVA), etc. In yet other embodiments, the midsole may include areas or pockets of a material, e.g. silicone, cast polyurethane. In some embodiments, the sole may include inserts such as one or more dampeners or bumpers to modify the dynamic response of the spring under a load. The inserts may be placed in open space for the spring structures such as voids or pockets 37, 71.

The footwear may have a traction sole, for example, configured for use in golf. Traction elements or cleats 30, 32 may be disposed on the ground-engaging element 8 and arranged in a pattern having a generally transverse alignment along the curved structure of the ground-engaging element. In some embodiments, the traction elements are located on the convex element just fore and aft of the pivot axis 21 or apex of the convex element, as seen in FIGS. 2-8, for example. The location of the traction elements may be adapted to provide traction for a wearer while playing golf. Golf players use spiked shoes for safer and more stable walking, standing on wet grass and slopes, and to provide a secure grip during swings. FIGS. 2-8 show a golf shoe including several small non-replaceable traction elements 30. These traction elements are situated mainly along the periphery of the outer surface of the ground-engaging element. As seen in the example of FIGS. 2-8, the sole assembly also may include a plurality of standard replaceable traction cleats 32, which serve as the main traction elements due to their larger size relative to elements 30, which are optional. In one exemplary embodiment, sets of such main traction elements are positioned along the ground-engaging element with one set of one or more elements disposed at about the center of the toe area of the sole assembly, another set of a plurality of elements (in this case four elements) arranged along a portion of the sole corresponding to the ball of the foot, and another set of a plurality of elements (in this case four elements) in a heel portion of the sole assembly 4. The traction elements may be arranged in a pattern showing alignment along the curved structure of the ground-engaging element. For example, the traction elements may be arranged in pairs along a longitudinal axis of the sole assembly with traction elements at lateral and medial sides of the sole assembly and each pair of traction elements aligned in a transverse direction of the shoe. The embodiment shown in FIGS. 9-13 illustrates a different pattern of traction elements 30. These may be replaceable or non-replaceable traction elements. The transverse slots 35 shown may be used to hold the receptacles for the replaceable cleats.

The traction elements 30, 32 may be coupled to the ground-engaging element 8 via openings in the ground-engaging element that are adapted to receive and hold the cleats in place. In some embodiments, the traction elements may be spikes or cleats 32. The spikes may be made of a rigid material, or a relatively soft or firm but flexible material, as used in modern golf shoes. In other embodiments, the cleats may be permanently attached to the ground-engaging element, for example, as shown in FIGS. 2-8.

The ground-engaging elements 30, 32 may further include a random or repeating pattern of differences in elevations or ridges, which may contribute to traction between the shoe and the ground. For example, FIG. 5 shows an indented surface surrounding traction elements and an indented surface forming a curved line along a longitudinal axis running from a traction element in the forefoot section to an opening in the ground-engaging element below the heel. The opening in the bottom of the heel may be used to help keep the flexibility of the sole in the area indicated.

The soles of the conventional rocker shoes may have a considerable thickness.

The golf shoe 1 further includes a shoe upper 5 that may be connected to the sole assembly, for example by adhesive bonding and via a solid and hard, but flexible insole. The shoe upper may be made of any suitable material, for example but not limited to leather, suede, neoprene, mesh, synthetics, or fabrics, or any combination of such materials.

The inventive subject matter is further directed to method for making a sole assembly for a golf shoe by molding a foot-supporting element, a spring system, and a ground-engaging element in a single-shot or multiple shot injection molding process, creating a monolithic midsole or entire assembly. Examples of single molded sole assemblies are shown in the attached figures. A monolithic structure may have a homogenous or heterogeneous composition. It may have varying material properties, such as varying density, durometer, spring rates, etc. For example, the spring effect may be accomplished by the design and shape of the sole assembly.

The inventive subject matter is further directed to a method for making a sole assembly by preparing a foot-supporting element and an ground-engaging element to form a sole assembly, and disposing a spring system between the foot-supporting element and the ground-engaging element so that the sole assembly comprises a geometric shape that is rounded convexly in the walking direction to convey the benefits of rocker shoe technology.

The inventive subject matter further contemplates a method for making such traction footwear and a method for using such traction footwear.

Persons skilled in the art will recognize that many modifications and variations are possible in the details, materials, and arrangements of the parts and actions which have been described and illustrated in order to explain the nature of the inventive subject matter, and that such modifications and variations do not depart from the spirit and scope of the teachings and claims contained therein.

All patent and non-patent literature cited herein is hereby incorporated by references in its entirety for all purposes. 

1-31. (canceled)
 32. A shoe comprising: a sole assembly having a forefoot section, a midfoot section and a rearfoot section, the sole assembly being configured in an unloaded state so that through (i) the midfoot section and at least (ii) the forefoot and/or rearfoot sections, it has an overall convex or outwardly bent curvature along a longitudinal cross-section of the sole assembly that is configured to allow rotation around a pivot axis disposed transversely to the longitudinal axis of the sole assembly in a midfoot section of the shoe; and a plurality of replaceable traction elements disposed in receptacles formed in the ground engaging element of the sole assembly.
 33. The shoe of claim 32 wherein a pair of the traction elements are disposed on the sole assembly just aft of the pivot axis, and a pair of the traction elements are disposed on one the sole assembly just fore of the pivot axis, one element in each pair being disposed along the medial periphery of the sole assembly and the other being disposed along the lateral periphery of the sole assembly.
 34. The shoe of claim 32 wherein the sole assembly includes a ground engaging element comprising a monolithic plate-like structure.
 35. The shoe of claim 32 wherein the sole assembly comprises a mechanical spring system with a plurality of springs at least one of which is disposed in a midfoot section of the shoe, and the sole assembly includes a ground engaging element comprising a plate-like structure that is coupled to ground-facing portions of the springs.
 36. The shoe of claim 35 further comprising a foot-supporting element coupled to opposing, foot-facing portions of the springs.
 37. A sole assembly comprising: a foot-supporting element; a ground-engaging element; and a plurality of mechanical spring elements disposed between and coupled to the foot-supporting element and the ground-engaging element so as to provide a spring system that is resiliently collapsible or compliant in a forefoot, midfoot, and/or heel section of the sole assembly, the spring elements being spaced along the longitudinal axis of the midfoot and forefoot and/or rearfoot sections and substantially along the entire length and width of said sections; and when the shoe is in an unloaded state, the ground-engaging element, through (i) the midfoot section and at least (ii) the rearfoot section, has an overall convex or outwardly bent curvature along a longitudinal cross-section of the sole assembly so that the sole assembly is configured with a pivot in the midfoot section that allows for rotation of the rearfoot section around the pivot.
 38. The sole assembly of claim 37 further comprises a plurality of receptacles configured to each receive a replaceable traction element suitable.
 39. The sole assembly of claim 37 wherein the foot-supporting element, ground-engaging element, and spring elements are integrated as a single monolithic piece.
 40. The sole assembly of claim 39 wherein the sole assembly comprises one or more thermoplastic materials.
 41. The sole assembly of claim 37 wherein the spring system includes spring elements in a wavy profile comprising a plurality of waves with peaks and troughs oriented along the longitudinal axis of the sole assembly.
 42. The sole assembly of claim 41 wherein the spring elements in the wavy profile are integrated as a single monolithic piece.
 43. The sole assembly of claim 41 wherein the wavy profile starts in the forefoot section of the sole assembly shoe and extends at least through the midfoot section, and the wavelength progressively increases from the forefoot section into the midfoot section of the sole assembly where the amplitude of the waves maximizes and thereby provides a pivot axis.
 44. The sole assembly of claim 43 wherein the amplitude of the waves in the rear-foot section does not exceed that maximum amplitude of waves in the midfoot section.
 45. The sole assembly of claim 37 wherein the overall convex or outwardly bent curvature along a longitudinal cross-section of the sole assembly extends through the forefoot section through the rearfoot section.
 46. The sole assembly of claim 37 wherein the spring system comprises a series of reinforcing ribs or tubular members that are positioned in a transverse direction along the longitudinal axis of the sole assembly.
 47. A sole assembly, comprising: a plurality of rigid traction elements disposed on a ground-facing surface of the sole assembly; the sole assembly comprising one or more spring elements disposed between a foot-supporting element and a ground-engaging element of the sole assembly; and, when the shoe is in an unloaded state, the ground engaging element through (i) the midfoot section and at least (ii) the forefoot and/or rearfoot sections has an overall convex or outwardly bent curvature along a longitudinal cross-section of the sole assembly; and and thereby the combination of the convex curvature and the spring system provides a feedback to the wearer of the shoe indicating the position of an actual balance point.
 48. The sole assembly of claim 47 further comprising a spring system disposed between the foot-supporting element and the ground-engaging element of the sole assembly, and wherein the spring system is configured to provide a rocker effect.
 49. The sole assembly of claim 48 wherein the spring system comprises a wavy longitudinal cross-sectional profile positioned in a forefoot section of the sole assembly, and wherein the wavy profile reaches a maximum at about a pivot point of the sole assembly.
 50. The golf shoe of claim 47 wherein the traction elements are disposed on the ground-engaging element and arranged in a pattern having an alignment along lateral and medial sides of a longitudinal axis of the golf shoe, wherein pairs of traction elements have a transverse alignment along the golf shoe.
 51. A method for making a monolithic structure comprising: in one more steps, introducing thermoplastic material into one or more mold components configured to mold a foot-supporting element; a ground-engaging element; and a plurality of mechanical spring elements disposed between and coupled to the foot-supporting element, and the ground-engaging element, the springs elements being spaced along the longitudinal axis of the midfoot and forefoot and/or rearfoot sections, and substantially along the entire length and width of said sections, and when the shoe is in an unloaded state, the ground-engaging element through (i) the midfoot section and at least (ii) the rearfoot section has an overall convex or outwardly bent curvature along a longitudinal cross-section of the sole assembly so that the sole assembly is configured with a pivot in the midfoot section that allows for rotation of the rearfoot section around the pivot; and allowing the thermoplastic material to form into the aforesaid elements.
 52. The method of claim 51 wherein the molding method comprises a single-shot molding process for producing the monolithic structure in a single step. 